Melanoma, a cancer usually grown out of melanocytes in the skin, mucous membranes, or luminal membrane, is the most malignant form of skin cancer. It is prone to metastasis when melanoma cells spread to distant sites in the body. Statistics indicates that more than 80% of skin cancer deaths are due to melanoma. Melanoma can develop anywhere on the skin, including the skin at body truck, feet, toes, or fingers.
It is likely that a number of factors, e.g., environmental and genetic ones, contribute to the development of melanoma. For Caucasians in many developed countries, exposure to ultraviolet (UV) radiation from the sun is believed to be the main cause for melanoma when the UV radiation brings about DNA mutations in the skin cells. However, the etiology for melanoma in Asian or African, particularly the so-called acral melanoma, is not well understood.
Treatment of melanoma remains a great challenge today as the 5-year survival rates, which are highly correlated to the development stage of the cancer when initially detected, are 94%, 44%, 38%, and 4.6% for patients with stage I, stage II, stage III, and stage IV melanoma, respectively. Patients with early stage melanoma, after confirmed by biopsy, are generally treated with surgery on primary tumors, whereas those with late stage tumors, often require radiotherapy or chemotherapy after the surgical resection. Clearly, to find a therapy to improve survival rates for melanoma patients is imperative as the current survival number, especially for those with late stage tumors, is very low.
Because patients with late stage melanoma depend heavily on radiotherapy or chemotherapy, there remains an urgent need to develop effective therapeutic agents for treating and/or prevention of melanoma.